You were a holy priest, who traveled around to exorcise all the demons you could find. While you were traveling, this particularly nasty demon popped up on your shoulder. You were the only one who could see him, the demon of law, Trafalgar Law. He took an interest in you, and though you'd attempted to exorcise him many times, he always popped back up on your shoulder, whispering in your ear to attempt to get you to sin. As you were traveling on your trusted stallion, Fredd-Bear, otherwise known as Freddie, that damn demon popped up on your shoulder again.